Great Basin Naturalist


Annual energy budgets were calculated for three species of small mammals (Peromyscus maniculatus, Onychomys leucogaster, Reithrodontomys megalotis) from the northern Great Basin, Benton County, Washington. Individual ingestion rates were based on species activity, microclimate regime, coefficient of digestibility, caloric diet, and the cost for reproduction. For males and females, the estimated energy expenditures were: P. maniculatus, 6080, 5891; O. leucogaster, 5714, 6587; and R. megalotis, 4057, 3791 kcal/yr. By comparison, each species on an individual basis processes more energy annually than the more abundant species in the community, Perognathus parvus, but their total contribution to community energy flow is apparently minor. Integration of these results with other ecological parameters is necessary to develop new hypotheses on the role of small mammal consumers in cold desert ecosystems.